Federal state budgetary institution “Russian Research Centre of Medical Rehabilitation and Balneotherapy”, Russian Ministry of Health, 121099, Moscow, Russia The majority of the enzymes need cofactors to manifest their catabolic activity. One group of the cofactors is comprised of metals. Many reactions involved in biosynthesis of biologically active compounds depend on the presence of macro- and microelements. In this context, mineral waters are of special importance as containing a great variety of mineral substances that exert the well-apparent influence on many biological processes, physiological and biochemical reactions. The mechanisms of their action on these processes are not yet properly understood and await an in-depth investigation. The present article is focused on the significance of mineral water (MW) consumption as one of the most important factors in the nutritional support of homeostasis of the digestive system and the organism at large. Special emphasis is placed on the influence of mineral waters on the nutrient transport and absorption processes in the small intestines with special reference to the role of peroxidation and certain adenosine triphosphatases. The paramount importance of maintaining the proper pH level is underscored. Bearing in mind the complicated character and poor knowledge of the mechanisms of action of mineral waters in the organism, the authors emphasize the necessity of their interdisciplinary investigation.